Results 51 to 60 of about 28,168 (221)

Photospheric Swirls in a Quiet-Sun Region

open access: yesThe Astrophysical Journal
Swirl-shaped flow structures have been observed throughout the solar atmosphere, in both emission and absorption, at different altitudes and locations, and are believed to be associated with magnetic structures. However, the distribution patterns of such
Quan Xie   +4 more
doaj   +1 more source

Solar Magnetized "Tornadoes": Relation to Filaments

open access: yes, 2012
Solar magnetized "tornadoes", a phenomenon discovered in the solar atmosphere, appear as tornado-like structures in the corona but root in the photosphere.
Gan, Weiqun   +4 more
core   +1 more source

Dynamic Coupling of Convective Flows and Magnetic Field during Flux Emergence [PDF]

open access: yes, 2011
We simulate the buoyant rise of a magnetic flux rope from the solar convection zone into the corona to better understand the energetic coupling of the solar interior to the corona. The magnetohydrodynamic model addresses the physics of radiative cooling,
Abbett   +35 more
core   +1 more source

Models of the Solar Photosphere [PDF]

open access: yesSymposium - International Astronomical Union, 1990
This review summarizes the main properties of the available theoretical models of the solar photosphere and the semiempirical models based primarily on observed spectra in different wavelength regions. LTE and non-LTE semiempirical models are compared with LTE and non-LTE theoretical (radiative equilibrium) models calculated with and without convective
openaire   +1 more source

Periodic Density Structures Observed in Ulysses Data: First Results

open access: yesJournal of Geophysical Research: Space Physics, Volume 131, Issue 3, March 2026.
Abstract Periodic density structures (PDSs) are advecting quasi‐periodic (periodicities between several minutes and several hours) density enhancements observed in the solar wind and corona. There is strong evidence that PDSs are formed at the Sun.
Brent M. Randol   +3 more
wiley   +1 more source

Derivation and Application of a Scaling between Hinode/SP and SDO/HMI Vector Magnetic Fields to Improve Magnetic Field Extrapolations

open access: yesThe Astrophysical Journal
Full-disk measurements of the solar magnetic field by the Helioseismic and Magnetic Imager (HMI) are often used for magnetic field extrapolations, but its limited spatial and spectral resolution can lead to significant errors.
C. Beck   +5 more
doaj   +1 more source

Limitations and Biases in the Retrieval of the Polar Magnetic Field. I. The Role of the Magnetic Filling Factor in Milne–Eddington Inversions of Simulated Hinode/SP Data

open access: yesThe Astrophysical Journal, 2023
We study the extent to which Milne–Eddington inversions are able to retrieve and characterize the magnetic landscape of the solar poles from observations by the spectropolarimeter on board Hinode.
Rebecca Centeno   +4 more
doaj   +1 more source

Connecting the Sun and the Solar Wind: The First 2.5 Dimensional Self-consistent MHD Simulation under the Alfv\'en Wave Scenario

open access: yes, 2012
The solar wind emanates from the hot and tenuous solar corona. Earlier studies using 1.5 dimensional simulations show that Alfv\'{e}n waves generated in the photosphere play an important role in coronal heating through the process of non-linear mode ...
Antolin   +28 more
core   +1 more source

Helioseismic analysis of the solar flare-induced sunquake of 2005 January 15 [PDF]

open access: yes, 2006
We report the discovery of one of the most powerful sunquakes detected to date, produced by an X1.2-class solar flare in active region 10720 on 2005 January 15.
Besliu-Ionescu, D.   +4 more
core   +1 more source

On the Freeze‐In Distance of Solar Wind Fluid Entropy Variability in the Corona

open access: yesJournal of Geophysical Research: Space Physics, Volume 131, Issue 3, March 2026.
Abstract The strong correlation between solar wind entropy and the frozen‐in ion charge state ratio O7+/O6+ ${\mathrm{O}}^{7+}/{\mathrm{O}}^{6+}$ indicates that entropy variability on timescales of hours or longer is preserved from its solar source. This prompts the question: where in the solar atmosphere does this entropy variability come from, and at
Aidan J. Nakhleh   +3 more
wiley   +1 more source

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